semiregular

Adjective

semiregular (not comparable)

1. Somewhat regular; occasional.
   • Although Lester must still see doctors on a semiregular basis for checkups, his health has returned to normal.2007 July 24, Bill Finley, “Victorious Night for Lester in His Return From Cancer”, in New York Times
2. Whose regular open sets form a base.
   • A space is semiregular iff the regularly open sets (3D) form a base for the topology.[…]Every space X can be embedded in a semiregular space.1970, Stephen Willard, General Topology, published 2004, page 98
3. Uniform (isogonal and isotoxal) with regular faces of two or more types, such that each vertex is surrounded by the same polygons in the same order.
   • It will be seen below that this semiregular polyhedron is of importance in its relationship to periodic minimal surfaces serving as a conceptual reference.1993, H. Terrones, A. L. MacKay, “The Geometry of Hypothetical Curved Graphite Structures”, in H. W. Kroto, J.E. Fischer, Deann Cox, editors, The Fullerenes, page 115
   • In a semiregular tessellation, there is an isometry of the plane carrying any vertex to any other vertex.1998, David A. Singer, Geometry: Plane and Fancy, page 35